The present work aimed at studying the effect of triethanolamine (TEA)
0.02% and dimethylsulphate (DMS) 0.025% from alkylating agents group as chemical mutagens on the correlation coefficients of some economic characters in the two Egyptian cotton varieties Menoufi and Giza 74, as well as the F ₁ and F2 populations of their hybrid. The experimentation work was carried out on M1 and M2 generations.

The results showed that positive phenotypic and genotypic correlations existed between fibre fineness and number of days to first flower in control plants. On the other hand, a negative genetic correlation was found between both traits in M1 induced by TEA and in M2 treated by DMS. Whereas, this genetic correlation was positive in M2 treated by TEA and in M1 induced by DMS. Positive genotypic correlations were found between fibre fineness and number of days to first open boll in control and in all mutant generations under study, except M2 treated by TEA where a negative genetic correlation was detected. The relationship between fibre fineness and boll weight in control showed positive phenotypic correlation, but negative genotypic correlation. After treatment by the two chemical mutagenes, positive genotypic correlations were found in all cases except in M1 treated by TEA, which showed negative genetic correlation. Positive genotypic correlations were found between fibre fineness and seed cotton yield per plant in M2 treated by the two chemical mutagens. On the other hand, negative genotypic correlations were found between both traits in M1 and control. Positive phenotypic and genotypic correlations were obtained between fibre fineness and lint percent treated by TEA in the two mutant generations, whereas, negative genotypic correlations were obtained between the two characters by DMS treatment in both mutant generations, as well as in control. After treatment with the two chemicals mutagens, positive phenotypic and genotypic correlations were found between fibre fineness and lint index in M1, while negative genotypic correlations were found between both traits in M2 as well as in control. Positive phenotypic and genotypic correlations were obtained between fibre fineness and seed index in control and M1 treated by TEA. In contrast, negative genotypic correlations between the two characters were found in the two mutant generations treated by DMS and the second mutant generation treated by TEA.